books

iTrader: (8)

I recently purchased and installed a used PFC, supposedly tuned by PFS for a hi flo, dp, intake. catback and smic. I have the same mods minus the hi flo. I wasn't comfortable with the maps that were in there, they don't look like any I have seen. So I had a few dyno runs to check the a/f ratios.
The following ratios were observed:
15.6 at 2100 rpm
14.7 at 3000 rpm
12 at 4,000 rpm
11.7 at 5000 rpm
11.7 at 6000 rpm

I was able to lower the ratios by .5 in the 4000 and above range by adding fuel to those particular cells. I am concerned about the 15.6 and 14.7 readings in the lower rpm ranges. There also seems to be higher knock values associated with those ranges. Since I have left the dyno I have attempted to lower the knock readings by adding fuel as much as 24% (106 to 130) to cells in the 2000-3600 for rpm ranges. I've also tried to add 5% to the PIM voltage setting for the 2000rpm range.
Any help would be appreciated.

thanks Dave

cewrx7r1

iTrader: (2)

But what P rows for 2000(N5) - 3600(N9) did you add the extra fuel?

books

iTrader: (8)

I changed rows P1-P7....did a map trace and this seemed to be the rpm and pressure areas where I was noticed more knock

cewrx7r1

iTrader: (2)

Boost does not go past 0psi on the 20X20 map untill
row P10. See below, was derived from the data in the owners manual.

ROW--------Boost Pressure, Relative/Gauge, PSI
20-----------19.4
19-----------16.6
18-----------13.8
17-----------10.9
16----------- 8.1
15----------- 6.6
14----------- 5.2
13----------- 3.8
12----------- 2.4

Do not worry about AFRs for rows below P15 if they are leaner than 12.

books

iTrader: (8)

thanks Chuck,

I need to ask why I shouldn't worry about rows below p15..I'm guessing it has to do with boost but not informed/educated in this arena...I'm also assuming you're saying that an afr of 15.6 at 2100 rpms is safe.

there seems to be a lot of conflicting info about knock values... I believe the datalogit manual says over 60 is udesirable , whereas the PFC manual; page 14 states to use it as a reference when tuning while yet another member implies that over 30 is not acceptable

should I pay any attention to the knock values or just go with what I saw on the dyno a/f ratios of 15.6 and less?

Is there any tested/proven reliable/measurable/quantative relationship between knock and afr with the stock sensors and the PFC?

just to throw a monkey wrench into the mix...these darn timing maps have over 40 cells with a negative split....a lot of them occuring in columns N3-N6 and rows P14-P20

thanks again for your help

Dave

cewrx7r1

iTrader: (2)

Too much data to cover by forum. Most of this can be found by intensive searching of the forum.

As for negtive split, what was your method for finding this? We normally copy both 20X20 matrix into EXCELL
and do a comparison of IGL to IGT. When you have IGL set up, then go adjust IGT to adjust the split you want.
YOU DO NOT WANT negative split.

If you want to talk, then mail me privately for my tel NBR.